Diarrhea

Question 1

Clinical definition of diarrhea

Answer 1

Increase in frequency, volume, or urgency of defecation with or without a change in consistency

Question 2

Normal stool frequency=

Answer 2

3 movements per week all the way up to 3 per day

Question 3

Physiologic definition

Answer 3

more than 200 gm of stool per day

Question 4

Normal input into the gut per day in liters

Answer 4

about 8.5…..only a quarter of this is from foodstuffs

Question 5

of the 8.5 liters that comes into the small intestine, how much is absorbed

Answer 5

Most…about 7 liters. Of the remaining 1.5 liters that enters the colon about 1.4 liters is absorbed

Question 6

What is the basis of normal fluid absorption

Answer 6

Na uptake

Question 7

Two modes of Na uptake in the small intestine?

Answer 7

• Na/ glucose co-transporter
• Na/ H exchanger
  FOUND IN THE VILLI….this is important because it shows that no villi = no fluid absorption

Question 8

Large intestinal Na uptake occurs via?

Answer 8

Epithelial Na channel (ENac)

Question 9

So diarrhea is increased intraluminal fluid that is a result of :

Answer 9

either decreased absorption or increased secretion…or both in some cases.
ALONG with Rapid Transit through GI

Question 10

Osmotic diarrhea characteristics

Answer 10

ingestion of some solute that can’t be absorbed and therefore acts as an osmotic agent by drawing fluid into the gut lumen

Question 11

Secretory diarrhea characterized by

Answer 11

Active secretion of electrolytes into the gut lumen

Question 12

Inflammatory diarrhea characterized by

Answer 12

inflammatory mediators stimulate secretion and the tight junctions of the epithelial barrier become loose

Question 13

see figures

Answer 13

ok

Question 14

Osmotic diarrhea causes

Answer 14

• Non-absorbable carbs
• Non-absorbably electrolytes
• Malabsorption syndromes

Question 15

The key to all secretory diarrhea is

Answer 15

excessive Cl- secretion into the gut

Question 16

How does cholera work

Answer 16

• invades enterocytes via the apical membrane and then migrates to the basolateral membrane (blood side)
• activates adenylate cyclase which activates cAMP which opens up chloride channels so that chloride can move into lumen
• Also inhibits Na/H co-transporter so that the only route of Na absorption is the Na Glucose exchanger
• The oral rehydration formula is a high salt drink containing glucose. This allows it to exploit the Na/Glucose transporter

Question 17

Volume of BM in secretory diarrhea?

Answer 17

High volume

Question 18

Volume of BM in osmotic diarrhea

Answer 18

moderate

Question 19

Which diarrhea resolves with fasting

Answer 19

Osmotic…b/c it is usually caused by something we eat

Question 20

Which diarrhea has very low flatulence levels?

Answer 20

secretory…osmotic = high

Question 21

stool pH in osmotic vs secretory

Answer 21

low pH in osmotic (below 5.3)

pH is 6-7 in secretory

Question 22

Osmolar gap?

Answer 22

In secretory diarrhea, most of the osmoles are electrolytes so the osmolar gap is low. Remember, this is calculated by taking a stool sample and sending it off for Na+ and K+ levels, mult these by 2, and then subtract from 290. Since secretory diarrhea has a ton of electrolytes in the stool the osmolar gap should be less than 50. In osmotic diarrhea it will be over 125

Question 23

Acute diarrhea time frame

Answer 23

less than 3 weeks

Question 24

Cause of acute diarrhea is almost always

Answer 24

infectious

Question 25

Acute diarrhea is generally always what type(s)

Answer 25

inflammatory or secretory

Question 26

Prognosis of acute diarrhea

Answer 26

self-limited

Question 27

Management of acute diarrhea

Answer 27

supportive

Question 28

Most common causes of infectious diarrhea in the US

Answer 28

• Viral
• E. Coli
• Campylobacter

Some Shigella, salmonella,

Giardia from streams
Cryptosporidium (mostly AIDS pts)
C Dif

Question 29

Third world causes

Answer 29

• Viral still
• Campylobacter
• E. Coli

CHOLERA

Entameba Histolytica
Salmonella and Shigella
Cryptosporidium (infants)

Question 30

MCC is travellers diarrhea

Answer 30

E. Coli

Question 31

Medical management of acute diarrhea

Answer 31

• No blood, no dehydration:
  Probably viral. give fluid and pepto
• No dehydration, blood +
  Probably bacterial but often self limited,
  Should do a stool sample. give fluids and pep
• Dehydration with or without blood
  Culture stool, IV fluids or oral rehydration form
  anti- diarrheal agent
• Bloody, dehydrated, septic
  Culture, IV fluid, IV cipro

Question 32

C. Diff risk factors

Answer 32

Antibiotic usage
Old age
hospitalization

Question 33

Cause of C. Diff colitis

Answer 33

The Cytotoxins A and B

Question 34

How do you diagnose C. Diff

Answer 34

Endoscopy- you will see the colitis

Stool assay for cytotoxins A and B

Question 35

Treatment of C. Diff

Answer 35

stop the offending Antibiotic
Used metronidazole or vancomycin to treat
Use cholestryamin to bind the toxins

Question 36

Lactase deficiency clinical features

Answer 36

• osmotic diarrhea
• they’ll have gas
• the stool will be acidic

Question 37

bacterial overgrowth =

Answer 37

bacteria present in small bowel

Question 38

What do bacteria in small bowel do to bile acid

Answer 38

unconjugate them, these unconjugated bile acids then move into the colon and cause secretory diarrhea

Question 39

Microscopic Colitis types

Answer 39

Lymphocytic collits and Collagenous Collitis

Question 40

Microscopic collitis presentation

Answer 40

chronic, watery, non-bloody diarrhea in adults

Question 41

Behcet’s disease…KNOW

Answer 41

Generalized vasculitis which presents with oral and genital apthous ulcers, uveitis, GI tract ulcers, and non-erosive arthritis

Question 42

Treat Behchets with

Answer 42

immunosuppresives

Question 43

check out red flags slides at teh end

Answer 43

ok